@Urappy sorry for the long wait, had some business yesterday.
oh, believe me, i KNOW AND FULLY UNDERSTAND what you're saying.
well, if you wanna say it that way, then there'll be lot's of things that's only assumed, right?
for example, have you ever actually asked your friend 'hey dude, are we even friends??'
no? if not, congrats, you've just assumed that he's your friend
you ever went to work 1 hour before work hour, because that's how long it usually take? again, you ASSUMED you'll arrive on time. so why do you do that?
have your dogs/cats/or any other pets ever said to you that they love you? no? congrats, again, you've assumed.
now you might've said that your friends and pets said that to you through body language. well, the same applied here. their body language SCREAMED they like each other.
there's some that's just apparent at plain sight. and what the girl's in saku's class assumed is not that they like each other. they assumed that they're dating. because they KNOW they like each other.
again, the fact that they like each other is plain for all to see.
as for 'the way you phrased this is kinda weird', i dunno how that's weird because i said '|opposite sex| did to you what uzaki did to saku|(or vice versa)|'
see? i used opposite sex, and also vice versa
now for your 'You can have a relationship similar to theirs without being in love.'
i dunno where you live, or how old are you (maybe you're still in elementary schools, who knows. no offense dude) but for most people above 10 years old, there's no pure opposite sex friendship. either you're a work friends, friend with benefit, friend toward the same goal, or friend with the same interest(by that i mean girls friends with a gay guy, or vice versa)
you might think you have an opposite sex friends, but IF that so called friends make an advance to you, and is not ugly, 99% of the time, the friendship will end, and something else will sprout.